{
  "port": 5431,
  "protocol": "both",
  "service": "PARK AGENT (park-agent)",
  "oneLiner": "Registered as PARK AGENT, but when it turns up it is usually a consumer router's own service.",
  "whatItIs": "IANA has 5431 registered as park-agent on TCP and UDP, an old entry with no published protocol description. The registered service is effectively extinct. What people do report finding on 5431 is a listener on consumer broadband routers — Broadcom-based Belkin, Linksys, and D-Link gateways — that disappears when UPnP is switched off, which points at the gateway's UPnP IGD control service; no vendor documentation confirms the port, so treat that as a field observation.",
  "exposure": {
    "verdict": "never",
    "note": "If this is your router answering, it is a device control surface — it must not be reachable from the WAN side."
  },
  "checkCommand": "curl -sS -o /dev/null -w '%{http_code}\\n' http://TARGET:5431/",
  "links": [
    {
      "title": "IANA port registry — 5431 (park-agent)",
      "url": "https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml?search=5431",
      "kind": "iana"
    }
  ]
}